I have created some points on a grid using a scatter node. Then I place boxes on these points by connecting a box node and the scatter node to a copy node.

I want to turn all these scattered cubes in to a rigid body sim, but want the boxes to act independently, not act as a single combined dynamic object.

How do I do this? I am using Houdini 13, so an't follow more recent tutorials.

Why are you using Houdini 13? I personally can't remember how RBDs worked that far back so can't help.

I have Mavericks OSX and am not sure a higher version will work. I am reluctant to upgrade to another OSX in case other apps stop working.

H13 introduced packed primitives and Packed RBD so the workflow would be probably the same
use Assemble SOP to make named packed primitives out of your boxes or if you already packed in your copy just create unique name attribute per primitive, then use as RBD Packed Object and the Bullet Solver
are there any specific issues you are running into?

Hello Thomas,


I can see there is an “Assemble” node at the Geometry level – is that what you mean? I do not follow how I create unique name attribute per primitive?

Is there a reason to use an Assemble node rather than a and Pack node?

The image below is my current setup. If I move up to the scene level and make the geo node that contains this node tree an RDB Object it creates a DOP network but the cubes act as a single object and when they fall do not fall apart when they hit another object.

https://ibb.co/CKbGs9c [ibb.co]

P.S. Another issue was having was that when I do get the boxes to act independently with a different way of creating the DOP network using and rdbpackedobject node (see image below) the boxes explode apart as if there is some collision force acting:

https://ibb.co/tL8HSKk [ibb.co]

I have been experimenting with the RBD Object and the RBD Fracture presets in the Rigid Body shelf tools and this seems to be why the boxes are recognized as either a single object or not. Presumably I should have used RBD Fracture?